Timing of hummingbird migration in southeastern Arizona: implications for conservation
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We examined the distribution and abundance of hummingbirds at three study sites in southeastern Arizona, where over 8,000 individuals of twelve species were banded. Banding occurred at two sites in the early 1990s and is currently active at the third. Anna’s (Calype anna), Black-chinned (Archilochus alexandri), and Rufous (Selasphorus rufus) Hummingbirds were the most abundant species. A massive southbound fall migration occurred at the study sites with fewer hummingbirds moving northward in spring. The large numbers of migrants were spaced over time within seasons, and the timing of peak migration for a species varied among years. Fall-migrant Black-chinned peaked earliest, followed by Rufous (predominantly juveniles), then Anna’s. Of these species, Rufous used the sites during migration only while the other species bred at one or more sites. Because the timing of migration differed among species, the resources critical for migration of each species likely differed as well. The implications for hummingbird conservation are discussed.